A totally specific, highly sensitive, rapid responding, accurate and reproducible phosphate electrode probe will be developed, based on the use of enzyme systems. The enzymes acid or alkaline phosphatase and glucose oxidase will be co-immobilized onto an oxygen or peroxide sensor, to constitute the phosphate probe. The variation of either of these two species, will be proportional to the phosphate concentration. The electrode configuration will be optimized to give long lifetime, high selectivity, good accuracy and reproducibility, sensitivity, and be capable of operation both in vivo and in vitro.
